Staple-leg guide mechanism

ABSTRACT

A guide piece  19  that enters between both legs  2   b  of a staple  2  is formed integrally on a pusher  16  that pushes a staple  2  as formed into a striking passage  12,  an inclined surface  20  that engages with a staple  2  to operatively retreat the pusher is formed on the guide piece  19  to be positioned thereon so as not to engage with the staple  2  until tip ends of staple legs  2   b  penetrate through sheets, and a driver plate  7  and a forming plate  6  are set to operate out of phase relative to each other so that the forming plate  6  begins forming of a non-formed staple  2   a  after staple legs  2   b  struck out have penetrated through the sheets.

TECHNICAL FIELD

The present invention relates to a staple-leg guide mechanism that bindssheets, by sequentially supplying straight non-formed staples charged ina cartridge to a striking part so as to form into a C-shape, supplyingthe C-shaped staple, striking passage to strike out the staple suppliedinto the striking passage, toward sheets, and using a clincher mechanismto bend those staple legs penetrating through the sheets, along a backsurface of the sheets.

BACKGROUND ART

Cartridge-type staplers for staple binding are known, in which acartridge accommodating therein a multiplicity of straight non-formedstaples is mounted to a magazine of an electrically driven stapler,non-formed staples in the cartridge are sequentially supplied to astriking part formed on a tip end of the cartridge, the non-formedstaple is formed just this side of the striking part by a forming plateto be C-shaped, and the formed staple is supplied into a strikingpassage, in which a driver plate slides, the driver plate strikes outthe formed staple from the striking passage so as to penetrate thestaple legs through sheets arranged on a lower surface of the cartridge.

The cartridge accommodating therein a multiplicity of staples is formedat a tip end thereof with the striking passage for striking-out of asingle leading staple toward the sheets, and the striking passage isformed between a front end surface of the cartridge and a face platemounted to a front end of the cartridge. The driver plate reciprocatedand driven by a motor provided on a body side of the electrically drivenstapler enters into the striking passage formed at the front end of thecartridge to strike out a staple arranged in the striking passage, andtip ends of staple legs penetrating through the sheets disposed on alower surface side of the cartridge are bent by the clincher mechanism.

With conventional, electrically driven staplers, an anvil arranged on alower surface of a non-formed staple is formed just this side of astriking passage, the anvil and a forming plate form the non-formedstaple to make-the same C-shaped, and the C-shaped staple is suppliedinto the striking passage by a pusher arranged below the anvil. When anon-formed staple is formed by the forming plate to be C-shape, thepusher is retreated to engage with a rear surface side of the staple,which is formed to be made C-shaped, to push the formed staple forwardwith a spring bias to supply into a groove of a face plate that definesthe striking passage. When a staple in the striking passage is struckout by the driver plate, the pusher pushes staple legs from rear surfacesides thereof so as to guide the staple legs struck out.

Forming of a non-formed staple is begun by the forming plate and staplelegs in the course of forming abut against the pusher whereby the pusheris retreated to engage with a rear surface side of the C-shaped stapleso as to push the staple toward the striking passage. When the pusher isretreated, a pushing force that pushes the staple arranged in thestriking passage from the rear may disappear, and guiding may not besufficiently performed in some cases. In the case where the staple legsof the formed staple are large in length, a large penetrating resistanceis generated until tip ends of staple legs penetrate through the sheets,after a crown portion is pushed by the driver plate and the tip ends ofthe staple legs struck out touch a surface of the sheets. When a pushingforce from the rear disappears as described above due to a largedistance between the driver plate and the tip ends of the staple legs,jam of staple legs is liable to generate. This tendency is remarkablespecifically in a stapler, in which a dimension between tip ends ofstaple legs and the sheets is set to be large.

As described above, as a technique for guiding of staple legs struck outin a stapler, in which a dimension between tip ends of staple legs andsheets is set to be large, it is known that guide grooves for guiding offront and rear surfaces and both right and left side surfaces of aformed staple are formed integrally on a face plate that defines astriking passage, and a staple formed by a forming plate is fed into theguide grooves by a driver plate, and further struck out toward thesheets from the guide grooves by the driver plate (see, for example,JP-Y2-2501487).

In such conventional electrically driven stapler, there is a need formechanisms such as a spring that supports the face plate verticallymovably and biases the face plate upward, a supporter for prevention offalling of a staple in the guide grooves formed on the face plate, etc.,which make the mechanisms complex and a cause for an increase in cost ofthe electrically driven stapler. Also, conventional mechanisms are setso that the driver plate strikes out a formed staple at the same timethe forming plate forms a non-formed staple to make the same C-shaped,and forming by the forming plate is begun to retreat the pusher before astaple struck out has penetrated completely through the sheet, so that arear surface of the staple struck out is not supported and an unstablestriking state is brought about, which makes a cause for failure, suchas jam, etc., in striking.

DISCLOSURE OF THE INVENTION

The present invention has its object to provide a staple-leg guidemechanism for electrically driven staplers, the mechanism being capableof effectively guiding staple legs when a C-shaped staple is struck outfrom a striking passage by a driver plate, and free from generation ofjam of staples, or the like.

In order to solve the problem, a staple-leg guide mechanism, in which aC-shaped staple supplied into a striking passage formed between a frontend surface of a staple supply passage and a rear surface of a faceplate arranged in front of the staple supply passage is struck outtoward sheets from the striking passage by a driver plate, according tothe invention has a feature in that a pusher having a pushing portion,by which a C-shaped staple is pushed into the striking passage, isprovided on a side of the front end surface of the staple supplypassage, a guide piece is formed on the pushing portion of the pusherand continuously projected toward a side of the face plate in a staplestriking-out direction through an inclined surface, so as to enterbetween both legs of a staple in the striking passage, and the inclinedsurface is formed in a position to engage with a staple when tip ends ofstaple legs struck out by the driver plate touch the sheets whereby thestaple legs are guided by the guide piece.

Also, the invention has a feature in that a staple supply passage thatguides a non-formed staple and a striking passage provided on a frontend surface of the staple supply passage to permit striking-out of aC-shaped staple, are formed in a cartridge that accommodates therein amultiplicity of non-formed staples and is detachably mounted on astapler body, and the staple-leg guide mechanism is formed on the frontend surface of the staple supply passage of the cartridge.

Also, the invention has a feature in that operation phases of the driverplate and the forming plate are shifted relatively to each other, sothat the forming plate starts forming of a non-formed staple afterstaple legs struck out by the driver plate penetrate through the sheets.Also, the invention has a feature in the provision of a pushing memberprovided at the back of the guide piece to push the guide piece towardthe striking passage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view showing an outline of an electrically drivenstapler, on which a cartridge according to the invention is mounted;

FIG. 2 is a partially fragmentary, vertical side view showing thecartridge mounted on the electrically driven stapler of FIG. 1;

FIG. 3 is a plan view showing a part of the cartridge of FIG. 2;

FIG. 4 is a perspective view showing an arrangement of a pusher, adriver plate, and a forming plate, which are formed on the cartridge ofFIG. 2;

FIG. 5 is a perspective view showing the pusher of FIG. 4 as viewed fromthe rear;

FIG. 6(a) is a front view showing a state before a staple bindingoperation is begun;

FIG. 6(b) is a fragmentary, vertical side view showing, in enlargedscale, a state before the staple binding operation is begun;

FIG. 7(a) is a front view showing a state, in which the driver platebegins striking of a staple;

FIG. 7(b) is a fragmentary, vertical side view showing, in enlargedscale, a state, in which the driver plate begins striking of a staple;

FIG. 8(a) is a front view showing a state, in which striking isperformed until tip ends of staple legs penetrate through sheets;

FIG. 8(b) is a fragmentary, vertical side view showing, in enlargedscale, a state, in which striking is performed until tip ends of staplelegs penetrate through the sheets;

FIG. 9(a) is a front view showing a state, in which a staple has beencompletely struck; and

FIG. 9(b) is a fragmentary, vertical side view showing, in enlargedscale, a state, in which a staple has been completely struck.

In addition, in the drawings, the reference numeral 1 denotes acartridge, 2 a staple, 2 a a non-formed staple, 2 b legs, 2 c a crownportion, 3 a striking portion, 6 a forming plate, 7 a driver plate, 11 astaple supply passage, 12 a striking passage, 14 a face plate, 16 apusher, 17 a pushing surface, 17a inclined surfaces, 18 a spring, 19 aguide piece, 20 an inclined surface, 21 a pushing member, 24 a driveshaft, and 15 slots.

BEST MODE FOR CARRYING OUT THE INVENTION

A mode for carrying out the invention will be described by way of anembodiment shown in the drawings. FIG. 1 shows an outline of anelectrically driven stapler according to the invention, and theelectrically driven stapler according to the embodiment is anelectrically driven stapler of equipment built-in type, which isincorporated in an apparatus such as copying machines, printingmachines, facsimile, etc. to automatically bind a predetermined numberof sheets, which are copied, printed, or received in facsimile, and inwhich straight staple stocks accommodated in a cartridge are formed intoa C-shape just before being struck out, and thereafter a staple formedto have a C-shape is struck out toward sheets.

The electrically driven stapler comprises a cartridge 1 thataccommodates therein a multiplicity of straight non-formed staples 2 andhas a striking portion 3 formed at a tip end thereof, a supply mechanism5 mounting thereon the cartridge 1 to supply a non-formed staple 2 a inthe cartridge 1 to the striking portion 3, a striking unit 4 including aforming plate 6 that forms a non-formed staple 2 a supplied to thestriking portion 3 into a C-shape, and a driver plate 7 that strikes outa staple 2 formed into a C-shape from the striking portion 3, and aclincher unit 8 accommodating therein a clincher mechanism 9 arrangedbelow the striking unit 4 to bend staple legs 2 b, which have beenstruck out by the driver plate 7 to penetrate through the sheets, alonga lower surface of the sheets.

As shown in FIGS. 2 and 3, the cartridge 1 comprises an accommodationportion 10 that accommodates a sheet staple S, in which a multiplicityof straight non-formed staples 2 are aligned and bonded to be formedflat, a staple supply passage 11, through which a bottom sheet staple Saccommodated in the accommodation portion 10 is led and guided to thestriking portion 3 formed at a front end of the cartridge 1, and astaple striking passage 12 that forms the striking portion 3 at a frontend of the staple supply passage 11. A sheet staple S accommodated inthe cartridge 1 abuts against the supply mechanism 5, which is arrangedbelow the cartridge 1, through an opening formed on a lower surface ofthe accommodation portion, and the supply mechanism 5 sends out a bottomsheet staple S from the accommodation portion 10 through an opening 13formed on a lower end wall of the accommodation portion 10 tosuccessively supply the same to the striking portion 3.

A face plate 14 is arranged leaving a space from a front end surface ofthe staple supply passage 11, and the staple striking passage 12 isformed between the front end surface of the staple supply passage 11 andthe face plate 14. An anvil 15 is formed at the front end of the staplesupply passage 11 to cooperate with the forming plate 6 to form anon-formed straight staple 2 a into a C-shape, so that a non-formedstraight staple 2 a arranged on the anvil 15 is formed into a C-shapedstaple 2 by the action of the forming plate 6.

A pusher 16 is arranged at the front end of the staple supply passage 11that faces the staple striking passage 12 formed between the front endsurface of the staple supply passage 11 and a rear surface of the faceplate 14, and the pusher 16 is arranged to be slidable along adirection, in which the formed staple 2 is supplied, and biased by aspring in a direction toward the striking passage 12. A pushing surface17 is formed at a front surface of the pusher 16 to engage with rearsurfaces of the formed staple legs 2 b to push the staple 2 forward, thepushing surface 17 engages with rear sides of the staple legs 2 b, whichare formed into a C-shape by the forming plate 6, and caused by twosprings 18 (see FIG. 5) arranged on both sides rearwardly of the pusher16 to push the staple 2 forward to supply the same into the strikingpassage 12 formed in the face plate 14. Inclined surfaces 17 a areformed on upper end edges of an outer side of the pushing surface 17 ofthe pusher 16 to engage with staple legs 2 b in the course of forming bythe forming plate 6 to move the pusher 16 rearwardly of the staple 2being formed.

As shown in FIG. 4, a guide piece 19 is formed integrally on the pusher16 to be pushed out further forwardly of the pushing surface 17 to beable to enter between staple legs 2 b of the formed staple 2, and aninclined surface 20 is formed on an upper portion of the guide piece 19.The guide piece 19 is formed to extend to a lower end of the strikingpassage 12, and sides of the guide piece 19 enter inner side surfaces ofstaple legs 2 b of a staple 2 struck out by the driver plate 7 wherebythe staple legs 2 b struck out from the striking passage 12 by thedriver plate 7 are guided at the inner side surfaces thereof.

The inclined surface 20 formed on the upper portion of the guide piece19 engages with a crown portion 2 c of a staple 2 struck out by thedriver plate 7 to bear the crown portion 2 c of the staple struck out,from an underside thereof to prevent jam of the crown portion 2 c causedby penetrating resistance. Further, the inclined surface 20 engages withthe crown portion 2 c of the staple 2 struck out by the driver plate 7to thereby act in a manner to retreat the pusher 16 rearward.

The inclined surface 20 is formed in a position to engage with the crownportion 2 c of the staple 2 struck out by the driver plate 7 in aposition, in which tip ends of the staple legs 2 b struck out from thestriking passage 12 contact with the sheets and arranged on a lowersurface side of the striking passage 12, legs 2 a of the staple 2 areguided at front surfaces and both outer sides thereof by the strikingpassage 12 until the tip ends of the staple legs 2 b penetrate throughthe sheets, and inner side surfaces of staple legs 2 b are furtherguided by the guide piece 19, so that stable striking is carried out. Apushing member 21 (see FIG. 5) arranged below a center of a rear surfaceof the pusher 16 pushes the guide piece 19 of the pusher 16 toward thestriking passage 12 to prevent the guide piece 19 from moving rearwardto make guiding unstable.

As shown in FIG. 4, a drive shaft 24 is provided to extend throughflanges 22, 23 formed on upper portions of the driver plate 7 and theforming plate 6, so that the driver plate 7 and the forming plate 6 arecaused to operate vertically through the drive shaft 24. The driverplate 7 operates integrally with the drive shaft 24, and slots 25fitting the drive shaft 24 loosely thereinto permit the forming plate 6to operate out of timing with the driver plate 7. That is, setting ismade such that as the drive shaft 24 operates, the driver plate 7operates to strike out the formed staple 2 arranged in the strikingpassage 12 from the striking passage 12 and the forming plate 6 beginsforming of a non-formed staple 2 a at a point of time when tip ends ofthe staple 2 penetrate through the sheets.

Also, when striking of the staple 2 is completed and the driver plate 7and the forming plate 6 return, the driver plate 7 first returns andoperates as the drive shaft 24-operates in a direction of return, andthe driver plate 7 and the forming plate 6 operate with phase differenceso that the forming plate 6 separates from the formed staple 2 after thedriver plate 7 retreats from the striking passage 12. In this manner,since timing for return of the driver plate 7 and the forming plate 6 isset, the staple legs 2 b formed by the forming plate 6 are preventedfrom spreading, and surely supplied by the pushing operation of thepusher 16 into a groove of the face plate 14 that forms the strikingpassage 12.

The operation of the embodiment will be described with reference toFIGS. 6(a) to 9(b). As shown in FIGS. 6(a) and 6(b), before striking ofa staple is begun, both the driver plate 7 and the forming plate 6 standby in upper initial positions and a leading staple 2 having been formedis arrangedd in the striking passage 12. A second staple 2 succeedingthe leading staple 2 is also formed at the time of the previous staplebinding operation to be supplied into the groove that forms the strikingpassage 12. The pusher 16 engages with inner side surfaces of the secondstaple legs 2 b and is caused by the pushing action of the springs 18 topush the leading staple 2 into the striking passage 12 through thesecond staple 2. The guide piece 19 of the pusher 16 enters between theleading staple legs 2 b to guide the staple legs 2 b at the inner sidesurfaces thereof.

When the drive shaft 24 operates, the driver plate 7 is operated by thedrive shaft 24 as shown in FIGS. 7(a) and 7(b) to enter into thestriking passage 12 to engage with the leading staple 2 to release theleading staple 2 from a state of connection with the second staple 2 andto strike out the leading staple in the striking passage 12 toward thesheets. In the meantime, the pushing surface 17 of the pusher 16 iscaused by the springs 18 to push the second staple 2 forward, and theleading staple legs 2 b are pushed forward by the second staple legs 2b, so that rear surfaces of the staple legs 2 b thus struck out areguided. Further, the guide piece 19 formed on the pusher 16 entersbetween both legs 2 b of the staple 2 struck out to guide the staplelegs 2 b from inside. Accordingly, the staple legs 2 b are guided by theface plate 14, the guide piece 19, and the second staple legs 2 b to bestruck.

As shown in FIGS. 8(a) and 8(b), until tip ends of staple legs 2 bpenetrate through sheets P after a point of time when the tip ends ofthe staple legs 2 b struck out by the driver plate 7 touch a surface ofsheets P, the inclined surface 20 formed on the upper portion of theguide piece 19 engages with a crown portion 2 c of the staple 2 tosupport the crown portion 2 c from under, and the guide piece 19 of thepusher 16 is positioned on inner side surfaces of the staple legs 2 b ofthe staple 2 struck out to guide the both legs 2 b at the inner sidesurfaces thereof, thus preventing jam from being generated bypenetrating resistance when the staple legs 2 b penetrate through thesheets. When the crown portion 2 c of the staple 2 struck out is struckbelow the inclined surface 20, the pusher 16 is retreated to cause theguide piece 19 to leave from between the staple legs 2 b struck out, andso there is no guidance for the inner side surfaces of the staple legs 2b, but at this point of time the tip ends of the staple legs 2 b havepenetrated through the sheets P, so that great penetrating resistance isnot generated and buckling or the like is not caused. Since this pointof time the forming plate 6 engages with a non-formed staple 2 a to formthe non-formed staple 2 a into a C-shape.

As shown in FIGS. 9(a) and 9(b), when the driver plate 7 is operated upto a bottom dead point, the crown portion 2 c of the staple 2 comes intoclose contact with a surface of sheets P, and the staple legs 2 bpenetrate through the sheets P and are then bent by the clinchermechanism 9 along a back surface of the sheets P, whereby the sheets arebound. While the drive shaft 24 returns to an upper initial positionafter the termination of staple binding, the driver plate 7 ascends andreturns together with the returning operation of the drive shaft 24 andthe forming plate 6 begins an ascending and returning operation afterthe driver plate 7 leaves the striking passage 12. The driver plate 7and the forming plate 6 operate out of return timing with each other inthis manner, whereby when the driver plate 7 leaves the striking passage12, a staple 2 having been formed into a C-shape by the forming plate 6is maintained in the formed state by the forming plate 6, in which statethe staple is pushed toward the striking passage 12 by the pusher 16 tobe supplied into the groove of the striking passage 12.

INDUSTRIAL APPLICABILITY

As described above, the staple-leg guide mechanism according to theinvention can prevent generation of jam or the like since a guide pieceis projectingly formed on a pushing surface of a pusher with an inclinedsurface therebetween, the pusher being provided with the pushing surfacethat pushes a staple, which is formed into a C-shape, into a strikingpassage, the guide piece is caused to enter between both legs of astaple in the striking passage, and the inclined surface is formed in aposition, in which the inclined surface engages with a crown portion ofa staple when tip ends of staple legs struck out by a driver plate toucha surface of sheet, so that a crown portion and legs of a staple struckout are surely guided and struck out until the staple arranged in thestriking passage is struck out by the driver plate and tip ends of thelegs penetrate through the sheet.

Also, since a cartridge that can be detachably mounted to a stapler bodyand accommodates therein non-formed staples is formed with a staplesupply passage, through which non-formed staples are guided, and astriking passage, through which staples formed into a C-shape are struckout to a front end surface of the staple supply passage, and astaple-leg guide mechanism is formed at the front end surface of thestaple supply passage, staples suffering jam can be readily removed bydismounting the cartridge from the stapler even in the case where jam orthe like is generated on staple legs. Also, staples having long staplelegs are stably guided in a vertical direction since a staple issupported from a rear surface side by a succeeding formed staple as in aconventional manner at the time of penetrating through sheet, andfurther a crown portion thereof is supported from under by the inclinedsurface.

Also, since a driver plate and a forming plate are set to operate out ofphase relative to each other so that the forming plate begins forming ofa non-formed staple after staple legs of a staple struck out by thedriver plate have penetrated through sheet, the pusher is not retreatedby a staple, which is formed by the forming plate, before tip ends ofstaple legs of a staple struck out by the driver plate touch the sheet,so that a staple struck out is stably guided. Also, at the time ofreturn, the forming plate holds a formed staple until the driver plateretreats from the striking passage, and the driver plate retreats fromthe striking passage to allow sure supplying into the striking passageby the pusher, so that staple legs of a staple as formed can beprevented from spreading to make supplying into the striking passageimpossible.

Further, since a pushing member that pushes a guide piece formed on thepusher toward the striking passage is provided on a rear side of theguide piece, the guide piece surely enters between staple legs of astaple struck out to surely guide the staple legs.

1. A staple-leg guide mechanism, in which a C-shaped staple suppliedinto a striking passage formed between a front end surface of a staplesupply passage and a rear surface of a face plate arranged in front ofthe staple supply passage is struck out toward sheets from the strikingpassage by a driver plate, the guide mechanism comprising: a pusherprovided on a side of a front end surface of the staple supply passageand having a pushing portion, by which the C-shaped staple is pushedinto the striking passage; and a guide piece formed on the pushingportion of the pusher and continuously projected toward a side of theface plate in a staple striking-out direction through an inclinedsurface, so as to enter between both legs of a staple in the strikingpassage, wherein the inclined surface is formed in a position to engagewith a staple when tip ends of staple legs struck out by the driverplate touch the sheets, so that the staple legs are guided by the guidepiece.
 2. The staple-leg guide mechanism according to claim 1, whereinthe staple supply passage that guides a non-formed staple and thestriking passage provided on the front end surface of the staple supplypassage for striking-out the C-shaped staple formed in a cartridge thataccommodates therein a multiplicity of non-formed staples and isdetachably mounted on a stapler body, and the staple-leg guide mechanismis formed on the front end surface of the staple supply passage of thecartridge.
 3. The staple-leg guide mechanism according to claim 1,wherein operation phases of the driver plate and the forming plate areshifted relatively to each other, so that the forming plate startsforming of a non-formed staple after staple legs struck out by thedriver plate penetrate through the sheets.
 4. The staple-leg guidemechanism according to claim 1, further comprising a pushing memberprovided at the back of the guide piece to push the guide piece towardthe striking passage.
 5. A cartridge for accommodating a non-formedstraight staple therein, comprising: a staple supply passage; a strikingpassage formed between a front end surface of a staple supply passageand a rear surface of a face plate; a pusher on a side of a front endsurface of the staple supply passage; a pushing portion on the pusher; aguide piece formed on the pushing portion; and an inclined surface on anupper end edge of an outer side of the guide piece, wherein the guidepiece is continuously projected toward the face plate through theinclined surface.
 6. A non-formed straight staple accommodated in acartridge, wherein the cartridge comprises: a staple supply passage; astriking passage formed between a front end surface of a staple supplypassage and a rear surface of a face plate; a pusher on a side of afront end surface of the staple supply passage; a pushing portion on thepusher; a guide piece formed on the pushing portion; and an inclinedsurface on an upper end edge of an outer side of the guide piece,wherein the guide piece is continuously projected toward the face platethrough the inclined surface.